Enterprise Vault 2010 forms and Organizational forms compatible?

We are upgrading our 9.0.2 environment to 10.0.1. We have a bunch of foreign offices that may not get the EV Outlook CLient for 10.0.1 installed before the upgrade. We are mostly at an Outlook 2010 install base. So basically I need to know if I must have the 10.0.1 client installed prior to upgrading to 10.0.1 EV server, or will the 9.0.2 client work with the new 10.0.1 Outlook forms?